Abstract : This study traces the development of two fire-fighting school smoke abatement systems, the Water Spray System and the After Burner System, from their inception to their states of development in mid-1975. Included are descriptions and comparisons of the two systems along with development and installation costs for the 1965-1975 fiscal years by OPN, O+M,N and MILCON categories. Conclusions regarding the utilization of the two systems are stated. (Author)